When you re blowing insulation it can get dusty and hard to see whether you ve got it deep enough around the entire attic.
Attic rafter insulation not deep enough.
Because the simplest and cheapest way to insulate an attic is to add material to the floor.
Attic rafter insulation is generally the most cost effective of any energy efficiency upgrade made to a house considering the potential cost savings that can be achieved on the monthly heating bills.
Insulation level are specified by r value.
The ideal solution especially if the rafters are not deep enough to allow for code minimum cavity insulation is to add rigid foam above the roof deck.
When using fiberglass insulation the pink stuff the attic roof rafter will need to be at least 16 deep.
But if the floor is covered in plywood you can t stuff enough insulation beneath it to do the job sufficiently not even in warm climates.
Sometimes there is enough insulation in the middle of the attic and very little along the eaves.
Because it s hard to insulate these areas many capes leak heat at the eaves a recipe for ice dams.
Some attic floors that already have a layer of insulation could benefit.
It is important that the insulation be evenly distributed with no low spots.
If there s still not enough room you can always add a layer of foam board or closed cell spray foam to the top of the roof topped by sheathing or other protective layers.
Plan to pull up the flooring and layer new insulation on top of the old.
If you cannot see any of the floor joists because the insulation is well above them you probably have enough and adding more may not be cost effective.
For example 2x4s would do but that is a lot of extra work.
Pick up the blower and insulation cellulose blown in ceiling insulation is a good choice for diyers.
Use care when reading the above linked un sourced handbook.
Even if you already have insulation in your roof you may still be losing heat if there is not enough.
Mark the desired level on different roof trusses around the attic before you start photo 4.
If the rafters are deep enough however it s more cost effective to work from the interior.
Install baffles against the roof sheathing between rafters so insulation does not seal up these avenues of air circulation.
Installation of attic or rafter insulation.
In addition to some of the structural considerations mentioned earlier furring can further reduce your existing attics head room.
If your attic insulation covers your joists and is distributed evenly you probably have enough.
R value is a measure of insulation s ability to resist heat traveling through it.
The higher the r value the better the thermal performance of the insulation.
Recommended home insulation r values.
One obvious solution would be to screw lengths of wood along the rafters to increase the depth.
To see how to add insulation out to the eaves see installing rafter vents.
